Lab: Debugging and Troubleshooting Code
Problems for exercises and homework for the “Programming Fundamentals Extended” course @ SoftUni.
Check your solutions here: https://judge.softuni.bg/Contests/419/Debugging-and-Troubleshooting-Code-Lab.
1. Multiply Evens by Odds
Create a program that reads an integer number and multiplies the sum of all its even digits by the sum of all its
odd digits:
Examples
Input
Output
12345
54
-12345
54
Comments
12345 has 2 even digits - 2 and 4. Even
digits has sum of 6.
Also it has 3 odd digits - 1, 3 and 5.
Odd digits has sum of 9.
Multiply 6 by 9 and you get 54.
Hints
1. Create a method with a name describing its purpose (like GetMultipleOfEvensAndOdds). The method
should have a single integer parameter and an integer return value. Also the method will call two other
methods:
2. Create two other methods each of which will sum either even or odd digits
3. Implement the logic for summing odd digits:
4. Do the same for the method that will sum even digits
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5. As you test your solution you may notice that it doesn't work for negative numbers. Following the program
execution line by line, find and fix the bug (hint: you can use Math.Abs())
2. Debugging Exercise: Holidays Between Two Dates
You are assigned to find and fix the bugs in an existing piece of code, using the Visual Studio debugger. You should
trace the program execution to find the lines of code that produce incorrect or unexpected results.
You are given a program (existing source code) that aims to count the non-working days between two dates given
in format day.month.year (e.g. between 1.05.2015 and 15.05.2015 there are 5 non-working days – Saturday and
Sunday).
Examples
Input
Output
Comments
01.05.2016
15.05.2016
5
There are 5 non-working days (Saturday / Sunday) in this period:
1-May-2016, 7-May-2016, 8-May-2016, 14-May-2016, 15-May-2016
01.05.2016
02.05.2016
1
Only 1 non-working day in the specified period: 1.05.2016 (Sunday)
15.05.2020
10.05.2020
0
The second date is before the first. No dates in the range.
22.02.2020
01.03.2020
4
Two Saturdays and Sundays:
 22.02.2020 and 23.02.2020
 29.02.2020 and 1.03.2020
You can find the broken code in the judge system: Broken Code for Refactoring. It looks as follows:
HolidaysBetweenTwoDates.cs
using System;
using System.Globalization;
class HolidaysBetweenTwoDates
{
static void Main()
{
var startDate = DateTime.ParseExact(Console.ReadLine(),
"dd.m.yyyy", CultureInfo.InvariantCulture);
var endDate = DateTime.ParseExact(Console.ReadLine(),
"dd.m.yyyy", CultureInfo.InvariantCulture);
var holidaysCount = 0;
for (var date = startDate; date <= endDate; date.AddDays(1))
if (date.DayOfWeek == DayOfWeek.Saturday &&
date.DayOfWeek == DayOfWeek.Sunday) holidaysCount++;
Console.WriteLine(holidaysCount);
}
}
Hints
There are 4 mistakes in the code. You’ve got to use the debugger to find them and fix them. After you do that,
submit your fixed code in the judge contest: https://judge.softuni.bg/Contests/419.
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3. Debugging Exercise: Price Change Alert
You are assigned to rework a given piece of code which is working without bugs but is not properly formatted.
The given program tracks stock prices and gives updates about the significance in each price change. Based on the
significance, there are four kind of changes: no change at all (price is equal to the previous), minor (difference is
below the significance threshold), price up and price down.
You can find the broken code here: Broken Code for Refactoring.
Input



On the first line you are given N - the number of prices
On the second line you are given the significance threshold
On the next N lines, you are given prices
Output




Don’t print anything for the first price
If there is no difference from the previous price the output message is: "NO CHANGE: {current price}"
In case of minor change: "MINOR CHANGE: {last price} to {current price} ({difference}%)"
In case of major change: "PRICE UP: {last price} to {current price} ({difference}%)" or "PRICE DOWN: {last
price} to {current price} ({difference}%)"
The percentage should be rounded to the second digit after the decimal point.
Examples
Input
Output
3
0.1
10
11
12
PRICE UP: 10 to 11 (10.00%)
MINOR CHANGE: 11 to 12 (9.09%)
3
0.1
10
10
12
NO CHANGE: 10
PRICE UP: 10 to 12 (20.00%)
Hints
1.
2.
3.
4.
Download the source code and get familiar with it
Deal with poor code formatting - Remove unnecessary blank lines, indent the code properly
Fix method parameters naming
Give methods a proper name
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